The present invention relates to an antiulcer agent. More specifically, the present invention relates to an antiulcer agent, including xcex1-lactalbumin as an active ingredient, which produces no side effects.
An ulcer (a peptic ulcer) is tissue damage resulting from necrosis to a certain depth of skin or mucous membrane in the esophagus, stomach, or duodenum, which is directly caused by hydrochloric acid or pepsin in gastric juice induced by stress, alcohol, a nonsteroidal anti-inflammatory drug (NSAID) such as indomethacin, or the like.
Specific examples of the antiulcer agent used for treatment of ulcers include an antacid which can neutralize gastric acid, and an anticholinergic drug, an H2 blocker, a proton pump inhibitor, and the like, which can suppress secretion of gastric acid.
Although specific examples of the antacids include sodium hydrogencarbonate, magnesium carbonate, aluminium hydroxide, and a mixture thereof, these have various problems. For example, they must be taken at frequent intervals because of the short duration of the action thereof, and the laxative action of the formulation is strong when it includes magnesium (Journal of Medicine, volume 27, page 2272, 1991).
Conventional anticholinergic drugs and H2 blockers (such as cimetidine) are known to have various problems. For example, the acute toxicitic dose thereof is low, side effects are caused by the binding thereof to respective receptors somewhere other than lesions (for example, cimetidine is known to cause hematologic disorders, hepatic disorders, renal disorders, endocrine disorders, mental or nervous disorders, digestive disorders, and hypersensitivity), and interference with other drugs occurs (Journal of Medicine, volume 27, page 2272, 1991; and DRUGS in JAPAN edited by the Japan Pharmaceutical Information Center, Jiho Inc., page 517, 1993).
Conventional proton pump inhibitors also have problems such as the generation of carotenoids (Journal of Medicine, volume 27, page 2272, 1991).
In contrast, specific examples of the antiulcer agents containing a protein, or a peptide as an active ingredient, include secretin, somatostatin, calcitonin, urogastrone, and the like.
Moreover, specific examples of a formulation derived from whey include methanol extract of whey (Japanese Unexamined Patent Application, First Publication No. Sho 62-277327, which is referred hereinafter to as Prior Art 1), whey protein (Japanese Unexamined Patent Application, First Publication No. Hei 1-268644, which is referred hereinafter to as Prior Art 2), and whey protein degradation product which is hydrolyzed by an enzyme (Japanese Unexamined Patent Application, First Publication No. Sho 56-32488, which is referred hereinafter to as Prior Art 3).
The peptide formulation, such as secretin, somatostatin, or calcitonin has a problem in that it is required to be administered by injection, which is accompanied by pain, and continuous administration is difficult (Journal of Medicine, volume 27, page 2272, 1991).
Although urogastrone is a peptide formulation for oral administration, it has problems in that the amount of urogastrone which can be prepared is limited, and in that the cost required for preparing urogastrone is high because the raw material from which urogastrone is prepared by purification is pregnant mare urine. Moreover, administration of urogastrone tends to cause side effects such as thirst, nausea, discomfort in the gastric region, diarrhea, constipation, and/or the like (DRUGS in JAPAN edited by the Japan Pharmaceutical Information Center, Jiho Inc., page 517, 1993).
Moreover, the methanol extract of whey (Prior Art 1) has a problem in that it is difficult to be used as a food material, because methanol is unsuitable in view of food safety, and the antiulcer substances prepared from other wheys (Prior Arts 2 and 3) have a problem in that the antiulcer action thereof is insufficient.
Therefore, antiulcer agents having neither the problems described above nor the side effects described above are awaited.
xcex1-lactalbumin is known to be a globular protein which accounts for approximately 25% (weight percent; the same units below unless specifically mentioned otherwise) of whey protein and has a molecular weight of approximately 14,100, and to play a part in a synthesis of lactose (xe2x80x9cComprehensive Encyclopedia of Milkxe2x80x9d edited by Kunio Yamauchi and Kenkichi Yokoyama, Asakura-Shyoten Co., Ltd., page 35, 1992). Moreover, xcex1-lactalbumin is known to have a gelation property and to be included in foods for masking effects or quality improvement, as well as in albumen substitutes, kneaded foods, or the like (xe2x80x9c""94 The Present and the Future of Protein and Peptide Foodsxe2x80x9d, Seed * Planning Co., Ltd., page 37, 1994).
However, xcex1-lactalbumin is not known to have strong antiulcer action, and this is not disclosed in any literature.
As is obvious from the prior art described above, although antiulcer agents for oral administration having few side effects are awaited, substances have not yet been discovered having superior effects.
As a result of extensive research aimed at obtaining more effective antiulcer agents, the inventors of the present invention discovered that xcex1-lactalbumin has antiulcer effects in vivo, and have thereby completed the present invention.
The present invention was made in view of the circumstances described above, and an object of the present invention is to provide an antiulcer agent, for oral administration, which produces few side effects.
The present invention, which can overcome the problems described above, is an antiulcer agent including xcex1-lactalbumin as an active ingredient, wherein xcex1-lactalbumin is preferably included in an amount of at least 0.5 mg per 1 g of the antiulcer agent. Moreover, xcex1-lactalbumin is more preferably included as an active ingredient in an amount of 1 mg per 1 g of the antiulcer agent.